tidy-up: delete unused build configuration settings

[vszakats]

Delete unused macros (most of them feature guards):

• CURL_INCLUDES_SYS_UIO [1]
• HAVE_ALLOCA_H [2]
• HAVE_CRYPTO_CLEANUP_ALL_EX_DATA (unused since de71e68)
• HAVE_DLFCN_H
• HAVE_DLOPEN
• HAVE_DOPRNT
• HAVE_FCNTL
• HAVE_GETHOSTBYNAME [3]
• HAVE_GETOPT_H
• HAVE_GETPASS
• HAVE_GETPROTOBYNAME
• HAVE_GETSERVBYNAME
• HAVE_IDN_FREE*
• HAVE_INET_ADDR
• HAVE_IOCTL
• HAVE_KRB4
• HAVE_KRB_GET_OUR_IP_FOR_REALM
• HAVE_KRB_H
• HAVE_LDAPSSL_H
• HAVE_LDAP_INIT_FD
• HAVE_LIBDL
• HAVE_LIBNSL
• HAVE_LIBRESOLV*
• HAVE_LIBUCB
• HAVE_LL
• HAVE_LOCALTIME_R
• HAVE_MALLOC_H
• HAVE_MEMCPY
• HAVE_MEMORY_H
• HAVE_NETINET_IF_ETHER_H
• HAVE_NI_WITHSCOPEID
• HAVE_OPENSSL_CRYPTO_H
• HAVE_OPENSSL_ERR_H
• HAVE_OPENSSL_PEM_H
• HAVE_OPENSSL_PKCS12_H
• HAVE_OPENSSL_RAND_H
• HAVE_OPENSSL_RSA_H
• HAVE_OPENSSL_SSL_H
• HAVE_OPENSSL_X509_H
• HAVE_PEM_H
• HAVE_POLL
• HAVE_RAND_SCREEN
• HAVE_RAND_STATUS
• HAVE_RECVFROM
• HAVE_SETSOCKOPT
• HAVE_SETVBUF
• HAVE_SIZEOF_LONG_DOUBLE
• HAVE_SOCKIO_H
• HAVE_SOCK_OPTS
• HAVE_STDIO_H
• HAVE_STRCASESTR
• HAVE_STRFTIME
• HAVE_STRLCAT
• HAVE_STRNCMPI
• HAVE_STRNICMP
• HAVE_STRSTR
• HAVE_STRUCT_IN6_ADDR
• HAVE_TLD_H
• HAVE_TLD_STRERROR
• HAVE_UNAME
• HAVE_USLEEP
• HAVE_WINBER_H
• HAVE_WRITEV
• HAVE_X509_H
• LT_OBJDIR
• NEED_BASENAME_PROTO
• NOT_NEED_LIBNSL
• OPENSSL_NO_KRB5
• RECVFROM_TYPE*
• SIZEOF_LONG_DOUBLE
• STRERROR_R_TYPE_ARG3
• USE_YASSLEMUL
• _USRDLL (from CMake) [4]

[1] Maybe some related parts in m4/curl-functions.m4 and
configure.ac could also be deleted?

[2] Maybe the related comment can also be deleted in
packages/vms/generate_config_vms_h_curl.com

[3] There are more instances of this in autotools, but I did not dare to
touch those. Looked like it is used to detect socket support.

[4] This is necessary for MFC (Microsoft Foundation Class) DLLs to
force linking MFC components statically to the DLL. libcurl.dll
does not use MFC, so this define can be deleted.
Ref: https://docs.microsoft.com/cpp/build/regular-dlls-statically-linked-to-mfc

Closes #xxxx

[bagder]

How did you find these? Can we create a script or test or something for this?

[vszakats]

@bagder It was a byproduct of an effort in syncing autotools-cmake-Makefile.m32 builds to produce the exact same binaries ¹. I dumped command-line -D + curl-config.h / config-win32.h options for all three into sorted lists and started comparing. Then I git grep for those that were only used by some of the build tools.

Some unused settings are still being generated by autotools, e.g. most HAVE_OPENSSL_*_H ones, as the strings seem generated and not visible as-is, by grep. (UPDATE: well, they are visible, but I didn't try updating autotools files to stop generating them. Probably something to fix before merging.)

It's probably possible to automate this to some extent: The source for most of these settings is lib/curl_config.h.cmake, lib/curl_config.h.in and lib/config-*.h. So parsing them and then looking the results up in the source tree can work.

Footnotes

1. This was a success for the generated .o files which are now all identical. Besides the OS string, which is different for each build tool, so I synced those with patches for these tests. ↩

[vszakats]

Here's a rough attempt to automate it:

#!/bin/sh

autoheader configure.ac  # generate lib/curl_config.h.in

{
  grep -o -E    'set\([A-Z][A-Z0-9_]{3,}'          CMake/Platforms/WindowsCache.cmake | sed -E 's|set\(||g'
  grep -o -E -h '#define +[A-Z][A-Z0-9_]{3,}'      lib/config-*.h                     | sed -E 's|#define +||g'
  grep -o -E    '#cmakedefine +[A-Z][A-Z0-9_]{3,}' lib/curl_config.h.cmake            | sed -E 's|#cmakedefine +||g'
  grep -o -E    '#undef +[A-Z][A-Z0-9_]{3,}'       lib/curl_config.h.in               | sed -E 's|#undef +||g'
} | sort -u | grep -v -F 'HEADER_CURL_' | while read -r def; do
  c="$(git grep -w -F "${def}" | grep -v -E -c '(/libcurl\.tmpl|^lib/config-|^lib/curl_config\.h\.cmake|^CMakeLists\.txt|^CMake/Platforms/WindowsCache\.cmake|^packages/vms/config_h\.com|^m4/curl-functions\.m4|^acinclude\.m4|^configure\.ac)')"
  if [ "${c}" = '0' ]; then
    echo "${def}"
  fi
done

This misses some RECVFROM_* macros. These are present in curl_setup_once.h in a section that is #if 0-guarded since f9894f4.

After a few tweaks the results are not so bad. It missed these few unique cases: RECVFROM_* (see above), HAVE_GETHOSTBYNAME which has an #undef in curl_setup.h, HAVE_OPENSSL_RAND_H / _USRDLL are CMake-specific leftovers), and it catches a whole lot more:

HAVE_ALLOCA_H
HAVE_BROTLI_DECODE_H
HAVE_DECL_GETPWUID_R
HAVE_DLFCN_H
HAVE_DLOPEN
HAVE_DOPRNT
HAVE_FCNTL
HAVE_GETPASS
HAVE_GSSAPI_GSSAPI_KRB5_H
HAVE_GSSHEIMDAL
HAVE_GSSMIT
HAVE_HYPER_H
HAVE_IDN_FREE
HAVE_IDN_FREE_H
HAVE_INTTYPES_H
HAVE_IOCTL
HAVE_KRB4
HAVE_KRB_GET_OUR_IP_FOR_REALM
HAVE_KRB_H
HAVE_LDAPSSL_H
HAVE_LDAP_H
HAVE_LDAP_INIT_FD
HAVE_LIBBROTLIDEC
HAVE_LIBDL
HAVE_LIBNSL
HAVE_LIBPSL
HAVE_LIBPSL_H
HAVE_LIBRESOLV
HAVE_LIBRESOLVE
HAVE_LIBRTMP_RTMP_H
HAVE_LIBSOCKET
HAVE_LIBSSH
HAVE_LIBUCB
HAVE_LIBWOLFSSH
HAVE_LIBZSTD
HAVE_LOCALTIME_R
HAVE_MACRO_SIGSETJMP
HAVE_MALLOC_H
HAVE_MEMCPY
HAVE_MSH3_H
HAVE_NETINET_IF_ETHER_H
HAVE_NGHTTP2_NGHTTP2_H
HAVE_NGHTTP3_NGHTTP3_H
HAVE_NGTCP2_NGTCP2_CRYPTO_H
HAVE_NGTCP2_NGTCP2_H
HAVE_NI_WITHSCOPEID
HAVE_OPENSSL_PKCS12_H
HAVE_O_NONBLOCK
HAVE_PEM_H
HAVE_POLL
HAVE_QUICHE_H
HAVE_SIGNAL_FUNC
HAVE_SIGNAL_MACRO
HAVE_SOCKET_H
HAVE_SOCKIO_H
HAVE_SOCK_OPTS
HAVE_SSL_GET_ECH_STATUS
HAVE_SSL_H
HAVE_STDINT_H
HAVE_STDLIB_H
HAVE_STRCASESTR
HAVE_STRLCAT
HAVE_STRNCMPI
HAVE_STRSTR
HAVE_STRUCT_IN6_ADDR
HAVE_SYS_UIO_H
HAVE_TLD_H
HAVE_TLD_STRERROR
HAVE_UNAME
HAVE_USLEEP
HAVE_WINLDAP_H
HAVE_WOLFSSH_SSH_H
HAVE_WRITEV
HAVE_X509_H
HAVE_ZSTD_H
NEED_BASENAME_PROTO
NEED_LBER_H
NOT_NEED_LIBNSL
OPENSSL_NO_KRB5
PACKAGE_BUGREPORT
PACKAGE_NAME
PACKAGE_STRING
PACKAGE_TARNAME
PACKAGE_URL
PACKAGE_VERSION
SELECT_QUAL_ARG5
SELECT_TYPE_ARG1
SELECT_TYPE_ARG234
SELECT_TYPE_ARG5
SELECT_TYPE_RETV
STRERROR_R_TYPE_ARG3
USE_ECH
USE_NGTCP2_CRYPTO_GNUTLS
USE_NGTCP2_CRYPTO_OPENSSL
USE_YASSLEMUL

Some of these may be used by external headers (e.g. OPENSSL_NO_KRB5), USE_ECH belongs to a future feature, some are automatically added by autotools, but some could surely be deleted.

[jay]

I think the HAVE_ ones at least should be ok. OPENSSL_NO_KRB5 is only defined by config-dos but I'm not sure why as I'd expect it to be defined by opensslconf.h.

[bagder]

OPENSSL_NO_KRB5 is only defined by config-dos but I'm not sure why

Yeah, that feels like an overstep. We should leave openssl to define those things.

[vszakats]

Rebased onto master.

[vszakats]

@bagder: At this point this is committable. The few FIXMEs are rather questions, that are beyond my insight to touch. Do you think I shall continue with this PR?